1. Field of the Invention
The invention pertains to the field of variable cam timing. More particularly, the invention pertains to variable cam timing (VCT) controls mounted in the camshaft.
2. Description of Related Art
In the prior art, variable cam timing controls are either mounted separately from the camshaft, phaser, or spool valve, and/or are present in the front cover of the internal combustion engine. Positioning of the variable cam timing controls separate from the housing increases the length of the valvetrain and thus increases the engine size.
For example, in prior U.S. Pat. No. 6,571,757, a variable force solenoid for controlling the position of a center mounted spool valve within a phaser is mounted separately or externally from the phaser and the spool valve. In U.S. Pat. No. 5,201,289, the actuator of known current proportional type has a housing separate form the camshaft for moving the spool valve. In JP 04-093108A, the solenoid valve providing fluid to a center passage of the camshaft and is mounted parallel to the camshaft.
Alternatively, the variable cam timing controls are mounted in the front cover of the internal combustion engine as in U.S. Pat. No. 6,435,154.
Due to the current demand in the automotive industry for improved or smaller packaging, there is a need for moving the variable cam timing controls relative to the variable cam timing mechanism or phaser, to decrease the packaging space of the VCT system.